TECHNICAL PROTOCOL FOR REGIONAL SUPPLEMENTARY COMPARISON APMP.AUV.A-S1

Transcription

1 TECHNICAL PROTOCOL FOR REGIONAL SUPPLEMENTARY COMPARISON APMP.AUV.A-S1 August 14, 2008 National Institute of Metrology (Thailand) (NIMT) Page 1 of 9

2 Preface It was agreed during the 8 th APMP TCAUV meeting in October 2007 in Sydney, Australia that an APMP Regional Supplementary Comparison on multi-frequency sound calibrator be carried out. After discussion on the process of both procuring an artefact and choosing the pilot laboratory, it was agreed that National Institute of Metrology (Thailand) (NIMT) would provide the artefact and would be the pilot laboratory. This document defines the technical protocol and specifies the calibration procedures necessary for the comparison, but not the procedures used for the realization of the artefact being compared. This document should be read in conjunction with the Guidelines for key comparisons carried out by Consultative Committees by T. J. Quinn which includes more details on the purpose and conduct of key comparisons in general. Participants The following eleven laboratories will participate: 1. KIM-LIPI, Indonesia 2. CMS/ITRI, Chinese Taipei 3. NMIA, Australia 4. NPLI, India 5. SCL, Hong Kong 6. SIRIM, Malaysia 7. NMIJ, Japan 8. NIM, China 9. NMC/A*STAR, Singapore 10. KRISS, Korea 11. NIMT, Thailand The contact details of the laboratories are attached at the end of this document. Page 2 of 9

3 Artefact to be circulated For this comparison, the multi-frequency sound calibrator chosen is Brüel & Kjær type 4226 Multifunction Acoustic Calibrator with serial number The artefact will be packaged within an aluminum box supplied by NMIT. Each participant is responsible for the transportation of the artefact to the next participant by a reliable international delivery service and by using the same packaging as NIMT has supplied. A participant may expect the artefact to be inspected at the customs authorities twice, namely for entry and for departure. The timetable must be strictly followed regardless of any delays caused by customs even if this would cause the participant to lose the opportunity to participate in this comparison. The artefact must be carefully packaged to avoid large temperature or pressure changes and sudden shocks to prevent it become less stable. Furthermore, careful treatment of the artefact is an essential requirement. The artefact must not be used for any purpose other than those associated with the calibration for this comparison. The artefact will return to NIMT for a check calibration each time two participants have performed their calibrations. This is being done so that the stability of the artefact can be monitored and so that results from different laboratories can still be compared even if a change should occur. Unpacking, Preparation and Packing Upon arrival, the participant is requested to note whether any damage has occurred to the carrying case or the artefact during transit. If any damage is observed, please contact the pilot laboratory. To prepare for use, the new batteries must be re-fitted to the artefact in the correct polarity. If unsure of battery fitting please contact the pilot laboratory who will immediately send the information. The battery for the artefact is type 4 x 1.5 V alkaline or Ni-Cd cells, IEC LR6 Preparation for transport. The batteries should be removed from the artefact before repacking in the carrying case. The carrying case should be put inside a paper box with soft material linings. The paper box should be closed with packaging tape covering the joint line around the box to ensure that they do not open during transit. Page 3 of 9

4 Measurements Each participant is to determine the sound pressure level, frequency and total distortion generated by the Multifunction Acoustic Calibrator by using calibration method described in the IEC 60942:2003 Standard. For the measurement of total distortion, it is suggested that two quantities namely Total Harmonic Distortion (THD) and Total Harmonic Distortion and Noise (THD+N) should be measured and reported by the participants, if possible. If a participant can measure only one quantity, it is acceptable provided it is clearly stated in the reported results which quantity i.e. THD or (THD+N) was measured. The generated sound pressure level, frequency, and THD and/or THD+N shall be measured at each frequency setting of the calibrator (see Table 1) with the calibrator s Function switch to Calibration, the Microphone switch to c and the Sound Field switch to Pressure. The generated sound pressure level shall be measured by the microphone method using calibrated standard microphone(s) of type LS2P as specified in IEC Standard. The frequency of the sound generated by the calibrator coupled to the microphone used to determine the output sound pressure level shall be measured at 94 db. The THD and/or THD+N in percent (measured over the frequency range from at least 22.5 Hz to 20 khz) at the 94 db and at the 114 db settings should be measured with the calibrator coupled to the microphone used to determine the output sound pressure level. Table 1 describes and summarises the quantities that should be measured and reported. Calibrator Frequency Setting (Hz) Measured Frequency ( 94 db Measured SPL (94 db Measured SPL (114 db THD (%) (94 db THD (%) (114 db THD+N (%) (94 db THD+N (%) (114 db 31.5 X X X X X X X 63 X X X X X X X 125 X X X X X X X 250 X X X X X X X 500 X X X X X X X 1000 X X X X X X X 2000 X X X X X X X 4000 X X X X X X X Page 4 of 9

5 8000 X X X X X X X X X X X X X X X X X X X X X Table 1. Quantities that should be measured and reported. Results shall be corrected to the reference environmental conditions specified in the IEC 60942:2003 Standard using the pressure and temperature coefficients of sound pressure level generated by the calibrator at each frequency given by the manufacturer and listed in Table 2. Frequency (Hz) Pressure coefficient (db/kpa) Temperature coefficient (db/k) Table 2. Pressure and temperature coefficients of sound pressure level generated by the calibrator. The operating handbook for the artefact has not been included. It is assumed that participants would be familiar with the operation and handling of this instrument. If any problems or questions arise during the calibration, the participants should contact the pilot laboratory who will forward a copy of the relevant information. Uncertainty Analysis It must be noted that the CIPM guidelines require uncertainty budgets to be submitted in advance of participation. Each participant shall submit their uncertainty budgets to the NIMT no later than August 31, 2008 and failure to do so may result in the exclusion of the participant. Minor revisions of the uncertainty budget will be accepted if submitted before the participant carries out the actual measurements. The ISO document Guide to the Expression of Uncertainty in Measurement Page 5 of 9

6 should be used as the reference document for the calculation and estimation methods. Uncertainty budget should be based on a coverage factor of k = 2. Reporting Results Each participant should report calibration results by using the standard certificate which would be normally issued to a customer. This report should include details of any deviations from the IEC 60942:2003 (Periodic tests) Standard. Estimated uncertainty caused by these deviations should be included in the uncertainty budget. The calibration certificate should also include the following information: 1. The method used to determine the pressure sensitivity level of the microphone. 2. The environmental conditions at the time calibration were preformed. 3. The orientation of the combined calibrator coupler and microphone, during calibration. The results should be posted to NIMT within two weeks of the transportation of the artefact to the next participant. An or fax should be sent to NIMT to announce that the results have been dispatched. Each participant also should inform NIMT when it receives the artefact from the previous participant and when it transports them to the next participant. Finance Each participant is responsible for its own costs and for the transportation fee of the artefact to the next participant so that the next participant does not have to pay anything when receiving the artefact using the door-to-door delivery method. An ATA carnet will be issued and delivered to the participants together with the artefact for Customs clearance. Each participant is also responsible for any damage to the artefact while they are away from NIMT. Timetable The timetable is as follows. It is essential that the artefact is transported to the next participant on time even if the measurements have not been completed by a participant. NMI Date of receipt of artefact from the previous participant (at least) Period for calibration, including transportation of artefact to the next participant Date of sending the artefact to the next participant (tentative) NIMT 3 weeks September 1, 2008 NMIA September 15, weeks September 29, 2008 Page 6 of 9

7 SCL October 13, weeks October 27, 2008 NIMT November 10, weeks November 17, 2008 KIM-LIPI December 1, weeks December 15, 2008 SIRIM December 29, weeks January 12, 2009 NIMT January 26, weeks February 2, 2009 CMS/ITRI February 16, weeks March 2, 2009 NIM March 16, weeks March 30, 2009 NIMT April 13, weeks April 20, 2009 KRISS May 4, weeks May 18, 2009 A*STAR June 1, weeks June 15, 2009 NIMT June 29, weeks July 6, 2009 NMIJ July 20, weeks August 3, 2009 NPLI August 17, weeks August 31, 2009 NIMT September 14, 2009 Note: Date of sending the artefact to the next participant is tentative. We estimate that it takes about 2 weeks to send the artefact to the next participant. However, because of the difference of the customs formalities of each country, we don t know how long it takes. Therefore, please ask your shipping agency or any Section in your NMI familiar with Customs for advice. Page 7 of 9

8 List of Contacts for the participating Laboratories NMI Economy Contact person Address NIMT Thailand Mr. Virat Plangsangmas 75/7 Rama VI Road, Thung Phayathai, Rajthevi Bangkok 10400, Thailand Dynamic Engineering Measurement Lab., CMS/ITRI Chinese Center for Measurement Standards ITRI, Dr. Chao-Jung Chen Taipei Bldg. 16, 321 Kuang Fu Rd., Sec.2, Hsinchu 300, Taiwan Standards and Calibration Laboratory SCL Hong Kong Mr. Y. K. Yan 36/F., Immigration Tower, 7 Gloucester Road, Wanchai, Hong Kong National Measurement Institute, P.O. Box NMIA Australia Mr. Tevor Bell 264, Bradfield Road, West Lindfield, NSW 2070, Australia National Metrology Laboratory, SIRIM SIRIM Malaysia Mr. Wan Aziz Wan Salleh Berhad, Lot PT 4803, Bandar Baru Salak Tinggi, Sepang, Selangor Darul Ehsan, Malaysia Indonesian Institute of Sciences, Research KIM-LIPI Indonesia Mr. Achmad Suwandi and Development Center for Calibration, Instrumentation and Metrology, Kompleks Puspiptek Serpong-Tangerang Tel (upper) Fax (lower) virat@nimt.or.th Chao-Jung.Chen@itri.org.tw ykyan@itc.gov.hk Trevor.Bell@measurement.gov.au wanaziz@sirim.my wandhini@yahoo.com Page 8 of 9

9 List of Contacts for the participating Laboratories NMI Economy Contact person Address Tel (upper) Fax (lower) NIM China Dr. Yang Ping Acoustic Laboratory, National Institute of Metrology, P.R.China, No 18, Bei San Huan Dong Lu, , Beijing, China KRISS Korea Mr. Jae Gap Suh Division of Physical Metrology, KRISS 1 Doryong-Dong, Yuseong-Gu, Daejeon , Korea jgs@kriss.re.kr NMC/A*STAR Singapore Dr. Chua Hock Ann Head, Mechanical Metrology, Metrology Department, National Metrology Center 1 Science Park Drive, Singapore NMIJ Japan Dr. Ryuzo Horiuchi Acoustics and Vibration Metrology Division, NMIJ, AIST, Tsukuba Central 3, Umezono, Tsukuba , Japan ryuzo.horiuchi@aist.go.jp NPLI India Dr. Ashok Kumar Acoustics Section, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi , India akumar@mail.nplindia.ernet.in Page 9 of 9